You're right, though, I should've said something like 'practical biofuels' are in their infancy. I was really more referring to algae oil based petroleum or butanol, as they seem like the most promising candidates for a net-energy positive and high energy density renewable fuel.
(also, it's very cool that you ran on that in the 80s, mind if I ask what kind of car it was, or if you'd had it customized?)
I'm not aware of any. Fertilizers?
> most current engines would need to all be retrofitted to run on anything much greater than E85 because of the greater corrosion
OTOH, once the engines get retrofitted (mostly a surface treatment, IIRC), ethanol burns much more cleanly, with much less combustion residue buildup. The early engines had corrosion problems, but once the surface treatment problem was solved, they enjoyed longer active life than their hydrocarbon-burning counterparts.
> mind if I ask what kind of car it was, or if you'd had it customized?
It was a stock Volkswagen Gol (a project derived from the 1st-gen Passat). You can see a couple pictures here: http://carros.uol.com.br/album/volkswagen_gol_historia_album.... At the time, my aunt worked at their engineering department and got one for me as a gift. Mine was a third-generation ethanol engine. She was involved in the ethanol vehicle project.
Most cars you can buy in Brazil today are bi-fuel and can run with any mix of ethanol and gasoline. It's often a good idea to run the car with ethanol from time to time to clean the engine, as ethanol actively removes residue buildup.
PS: It's not that far off though the US accounts for ~44% of the world’s gasoline consumption, but it's would take ~57% of the world's ethanol to switch every gas pump in the US to 10% ethanol.
The closest match is probably thermal depolymerization (http://en.wikipedia.org/wiki/Thermal_depolymerization)
The problem is not the fuel itself, but the possibility to scale up production. Petroleum is available in vast quantities compared to all biofuel feedstocks. Most biofuels today compete with food production, or are not very developed, like cellulose. Even cellulose would have a hard time scale to the sufficient quantities if all the technical problems were solved.
